Ms Foster said we in Northern Ireland understand the pain of the loss of a colleague, referring to a number of Northern Ireland MPs murdered during the Troubles including Robert Bradford.

"This is a very sad day for politics in the United Kingdom. I join others in thanking you, Mr Speaker, for the action that you have already taken in conveying to the Speaker of the House of Commons our deepest sympathy to her colleagues there," she told Stormont.

"The murder of Jo Cox was shocking. It was undoubtedly a tragic event that will live long in the memory. Thankfully, the murder of a Member of Parliament is a rare event, but we feel the loss all the more because of that.

"Outside of the murders carried out by Irish republicans in connection with the Troubles in Northern Ireland, this was the first murder of a Member of Parliament since 1812.

"Perhaps nowhere more than in Northern Ireland, we on all sides of the House understand the pain of the loss of a colleague, whether as Members of the Westminster Parliament, the old Stormont Parliament or those more broadly involved in politics in Northern Ireland.

"Although the threat to those involved in politics here is not what it once was, we must all still remain vigilant. However, we must never close our doors to those who elect us or become detached from those who send us here."

She said last Thursday was a dark day for politics, but above all, it was a tragedy for Ms Cox;s family and close friends.

"We especially remember her husband Brendan and her two young children," she said.

"I did not know Jo Cox personally, but it is clear from the many tributes to her and from talking to some of my Westminster parliamentary colleagues that she was a remarkable individual and was going to have a very strong, maybe even exceptional, career.

"Our prayers and sympathy go out to all those who knew Jo Cox personally in the difficult days that lie ahead.

"Jo’s murder serves as a timely reminder to all of us involved in politics that, despite the differences that we may have on one issue or another, there are values that are shared across the political spectrum and that we must never lose that thing that unites us. That was something very clear that came from her husband."

The DUP leader also said that we owe it to Ms Cox to "conduct ourselves in a manner that is consistent with the best traditions of democracy".

"That does not mean that we should not argue or differ, but it does mean that we should do so in a more respectful tone than is sometimes the case," she said.

"When I took over as First Minister, I made a call for us to do politics differently. We have made progress, but let this event help us to redouble our efforts in Northern Ireland.

"On this day, let us remember the words of President Kennedy that civility is not a sign of weakness and remember that this dreadful event can bring a new civility to politics and not just for a few days.